Connector/C++ supports the classic C++ API based on the JDBC4 specification. This allows an easy migration to Connector/C++ 8 for applications that use earlier versions of Connector/C++ (e.g., version 1.1). See also MySQL Connector/C++ 1.1 Developer Guide.

Note: JDBC API implementation uses the classic MySQL protocol and therefore it can work with older servers that do not support the X Protocol.

Sample code which uses Connector/C++ with classic C++ API

The following code demonstrates how to connect to MySQL Server using the classic C++ API. After the connection is established the code executes a simple SQL statement and reads the result from the server. The source file can be found in testapp/jdbc_test.cc in the Connector/C++ source tree. See Using Connector/C++ 8 for instructions on how to build the sample code.

Each program which uses the classic C++ API has to include <mysql/jdbc.h> header:

#include <mysql/jdbc.h>

To establish a connection to MySQL Server, get an instance of sql::Connection from a sql::Driver object returned by sql::mysql::get_driver_instance():

int main(int argc, const char **argv)
{
    sql::Driver * driver = sql::mysql::get_driver_instance();
 
    /* Using the Driver to create a connection */
 
    cout << "Creating session on " << url << " ..."
         << endl << endl;
 
    std::unique_ptr< sql::Connection >
      con{driver->connect(url, user, pass)};

The connect() method returns a pointer to a dynamically allocated connection object which is stored in a std::unique_ptr to ensure that the object is deleted when no longer needed. The same pattern is used for other API methods that return pointers to objects – it is responsibility of the caller to delete them. However, the driver instance should not be explicitly deleted, the connector takes care of freeing it.

Note: The get_driver_instance() function is not thread-safe. Either avoid invoking it from within multiple threads at once, or surround the calls with a mutex to prevent simultaneous execution in multiple threads.

These methods can be used to check the connection state or reconnect:

sql::Connection::isValid() checks whether the connection is alive
sql::Connection::reconnect() reconnects if the connection has gone down

We set the default schema of the connection and create a statement object that will be used to execute a query:

    con->setSchema(database);
 
    std::unique_ptr< sql::Statement > stmt{con->createStatement()};

To run simple queries that return a single result set use the sql::Statement::executeQuery() or sql::PreparedStatement::executeQuery() method. Both methods return sql::ResultSet objects. By default the classic API implementation buffers all result sets on the client to support cursors.

Note: If your query does not return a result set or if it returns more than one result set use the sql::Statement::execute() method instead.

    std::unique_ptr< sql::ResultSet >
      res{stmt->executeQuery("SELECT 'Welcome to Connector/C++' AS _message")};
 
    cout << "\t... running 'SELECT 'Welcome to Connector/C++' AS _message'"

The code below walks through the entire result set row by row using sql::ResultSet::next() method, which returns true if the row was successfully read. Otherwise it returns false which means we reached the end of the result set and there are no more rows to read. The actual data is obtained through the getXxxx() methods getInt(), getString(), etc. The columns can be indexed by numbers in the order they are given inside the result set starting from 1. Alternatively the column name can be used as a string index.

    while (res->next())
    {
      cout << "\t... MySQL replies: " << res->getString("_message") << endl;
      cout << "\t... say it again, MySQL" << endl;
      cout << "\t....MySQL replies: " << res->getString(1) << endl;
    }

Error handling is done using exceptions that derive from sql::SQLException class that is derived from std::runtime_error.

  catch (sql::SQLException &e)
  {
    /*
      The JDBC API throws three different exceptions:
 
    - sql::MethodNotImplementedException (derived from sql::SQLException)
    - sql::InvalidArgumentException (derived from sql::SQLException)
    - sql::SQLException (derived from std::runtime_error)
    */
 
    cout << "# ERR: SQLException in " << __FILE__;
    cout << "(" << "EXAMPLE_FUNCTION" << ") on line " << __LINE__ << endl;
 
    /* Use what() (derived from std::runtime_error) to fetch the error message */
 
    cout << "# ERR: " << e.what();
    cout << " (MySQL error code: " << e.getErrorCode();
    cout << ", SQLState: " << e.getSQLState() << " )" << endl;
 
    return EXIT_FAILURE;
  }

Here is the complete C++ code of the test sample for the classic C++ API:

/*
 * Copyright (c) 2008, 2024, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0, as
 * published by the Free Software Foundation.
 *
 * This program is designed to work with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms, as
 * designated in a particular file or component or in included license
 * documentation. The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have either included with
 * the program or referenced in the documentation.
 *
 * Without limiting anything contained in the foregoing, this file,
 * which is part of Connector/C++, is also subject to the
 * Universal FOSS Exception, version 1.0, a copy of which can be found at
 * https://oss.oracle.com/licenses/universal-foss-exception.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License, version 2.0, for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
 
 
/*
   Basic example of an application using JDBC API of Connector/C++
*/
 
/* Standard C++ includes */
 
#include <stdlib.h>
#include <iostream>
#include <sstream>
#include <stdexcept>
#include <memory>
 
 
#include <mysql/jdbc.h>
 
#define DEFAULT_URI "tcp://127.0.0.1"
#define EXAMPLE_USER "root"
#define EXAMPLE_PASS ""
#define EXAMPLE_DB "test"
 
using namespace std;
 
/*
  Usage example for Driver, Connection, (simple) Statement, ResultSet
*/
 
int main(int argc, const char **argv)
{
  const char   *url = (argc > 1 ? argv[1] : DEFAULT_URI);
  const string user(argc >= 3 ? argv[2] : EXAMPLE_USER);
  const string pass(argc >= 4 ? argv[3] : EXAMPLE_PASS);
  const string database(argc >= 5 ? argv[4] : EXAMPLE_DB);
 
  cout << endl;
  cout << "Connector/C++ standalone program example..." << endl;
  cout << endl;
 
  try {
 
    sql::Driver * driver = sql::mysql::get_driver_instance();
 
    /* Using the Driver to create a connection */
 
    cout << "Creating session on " << url << " ..."
         << endl << endl;
 
    std::unique_ptr< sql::Connection >
      con{driver->connect(url, user, pass)};
 
    con->setSchema(database);
 
    std::unique_ptr< sql::Statement > stmt{con->createStatement()};
 
    std::unique_ptr< sql::ResultSet >
      res{stmt->executeQuery("SELECT 'Welcome to Connector/C++' AS _message")};
 
    cout << "\t... running 'SELECT 'Welcome to Connector/C++' AS _message'"
         << endl;
 
    while (res->next())
    {
      cout << "\t... MySQL replies: " << res->getString("_message") << endl;
      cout << "\t... say it again, MySQL" << endl;
      cout << "\t....MySQL replies: " << res->getString(1) << endl;
    }
 
  }
  catch (sql::SQLException &e)
  {
    /*
      The JDBC API throws three different exceptions:
 
    - sql::MethodNotImplementedException (derived from sql::SQLException)
    - sql::InvalidArgumentException (derived from sql::SQLException)
    - sql::SQLException (derived from std::runtime_error)
    */
 
    cout << "# ERR: SQLException in " << __FILE__;
    cout << "(" << "EXAMPLE_FUNCTION" << ") on line " << __LINE__ << endl;
 
    /* Use what() (derived from std::runtime_error) to fetch the error message */
 
    cout << "# ERR: " << e.what();
    cout << " (MySQL error code: " << e.getErrorCode();
    cout << ", SQLState: " << e.getSQLState() << " )" << endl;
 
    return EXIT_FAILURE;
  }
 
  cout << endl;
  cout << "... find more at http://www.mysql.com" << endl;
  cout << endl;
  return EXIT_SUCCESS;
}